Investigation of cutting and specific cutting energy in turning of POM-C using a PCD tool: Analysis and some optimization aspects

Abstract

This paper focuses on turning a commonly used industrial plastic, unreinforced polyoxymethylene copolymer (POM-C), using a cutting tool made of polycrystalline diamond (PCD). Conducted experimental investigation was the basis for the analysis of the influence of cutting parameters on cutting energy, determination of specific cutting energy and construction of specific cutting energy consumption maps, the analysis of the relationship between the specific cutting energy and the un-deformed chip thickness, the evaluation of the machinability, and the analysis of cutting energy considering machinability. A multi-objective optimization problem with cutting energy and MRR as conflicting objective functions was also studied and solved using two optimization approaches. Observed correlations between cutting parameters and cutting energy or specific cutting energy are different compared to other studies that analysed different standard engineering materials. The depth of cut turned out to be the key cutting parameter for the achievement of a trade-off between the cutting energy and MRR. Variable influences of the feed rate and the cutting speed on cutting energy and specific cutting energy, depending on the depth of cut value, are also observed. Chip form turned out to be the prevalent criteria for the evaluation of unreinforced POM-C machinability. There is a combination of cutting parameter ranges and the range of cross sectional ratio (ratio of the depth of cut and feed rate) which ensure formation of favourable chip forms. Optimization of cutting parameter values can lead to substantial energy savings in removing a unit volume of unreinforced POM-C, either by observing only the cutting energy or by including the consideration of the machinability.